Market outcomes refer to observable patterns and anomalies in financial markets that cannot be fully explained by traditional rational finance theories. These outcomes show that prices and returns are often influenced by investor behaviour, emotions, and biases. Behavioural Finance helps explain why such patterns exist and why markets do not always remain efficient. Factors like overreaction, underreaction, herd behaviour, and psychological biases lead to abnormal returns and price movements. The following market outcomes highlight important deviations from rational market assumptions.
- Size Effect and Seasonality
The size effect refers to the tendency of small company stocks to earn higher returns than large company stocks over the long run. Traditional finance cannot fully explain this difference in returns. Behavioural Finance suggests that small stocks are often ignored or underestimated by investors, leading to mispricing. Seasonality refers to regular patterns in returns during certain periods, such as higher returns in January. Investor mood, tax planning, and calendar related behaviour influence these patterns. These effects show that market returns are influenced by behavioural and timing factors, not only fundamentals.
- Momentum and Reversal
Momentum refers to the tendency of stocks that performed well in the recent past to continue performing well in the short term. Investors often follow trends and buy winning stocks due to herd behaviour and overconfidence. Reversal occurs when past winners become losers and past losers outperform in the long run. This happens because investors initially overreact to information and later correct their mistakes. Behavioural Finance explains momentum as underreaction and reversal as overreaction. These patterns show that investor psychology affects price movements over different time periods.
- Post Earnings Announcement Drift
Post earnings announcement drift refers to the slow adjustment of stock prices after earnings are announced. Even when earnings information is public, prices continue to move in the same direction for some time. This indicates underreaction by investors. Many investors do not immediately process or believe new information. Behavioural biases like conservatism and limited attention cause this delay. Traditional finance assumes instant price adjustment, but this drift shows inefficiency. Behavioural Finance explains that investors gradually update their beliefs, leading to delayed price correction.
- Value Premium
Value premium refers to the higher returns earned by value stocks compared to growth stocks. Value stocks have low price to earnings or price to book ratios and are often seen as unattractive. Investors may avoid them due to pessimism or negative sentiment. Growth stocks, on the other hand, attract attention and optimism. Behavioural Finance explains value premium as a result of overreaction to bad news and over optimism for growth stocks. Over time, prices correct, and value stocks generate higher returns.
- Premium Puzzle
The premium puzzle refers to the difficulty of explaining why stocks earn much higher returns than risk free assets over the long term. Traditional finance models cannot fully justify this large difference using risk alone. Behavioural Finance explains this puzzle through loss aversion and fear of uncertainty. Investors demand a high premium to invest in risky assets because losses hurt more than gains feel good. Emotional discomfort and risk perception lead to higher expected returns on equities compared to safe investments.
- Excessive Volatility
Excessive volatility means that stock prices fluctuate more than justified by changes in fundamentals like earnings or dividends. Behavioural Finance explains this through investor emotions, speculation, and overreaction to news. Fear and excitement cause sharp price movements even when information impact is small. Herd behaviour and noise trading also increase volatility. Traditional finance assumes stable reactions, but real markets show frequent ups and downs. Excessive volatility highlights the strong role of psychology in market price movements.
- Bubbles
Bubbles occur when asset prices rise far above their intrinsic value and later crash sharply. Behavioural factors play a major role in bubble formation. Investors follow the crowd, ignore fundamentals, and believe prices will keep rising. Overconfidence and speculation drive demand. Media hype and social influence strengthen the bubble. When reality sets in, panic selling leads to a crash. Behavioural Finance explains bubbles as collective irrationality rather than rational market behaviour.